Rockers can be any head. The left had a few years (before yours) that had head defects.

Mopar (AH revision) or Melling, both are fine. Also Elgin.

That video does not have a tick sound. Do a compression test, at least for the front bank.

 

Thanks for looking Sienile! I didn't suspect from the noise that there were any worrisome valvetrain sounds coming out of there -- thanks for confirming. I'll be testing the compression/leakdown this weekend and that should hopefully give me some more information. It certainly would be great to find out that compression is still in spec -- seems like that would lead me toward a potentially bad injector which is a **** of a lot easier to change.

 

An injector would usually throw a P020x or P017x type code. Not always, but usually.

Did you gap your plugs to .043"?

 

The plugs were pre-gapped at 0.43 and I checked each one before putting them in.

The only perceptable symptom is modestly rough idle and some mild bucking when I let off the brake (no gas) in drive. The van seems to have all of its power in acceleration an and no obvious stumble when driving it. Other than that slight tick you hear in the video (which I think is the sound of injectors doing their job) there is nothing loud coming out of the engine.

The only code I can see with my cheapo scanner is P0306. My next step is a compression test, then I'll go from there.

 

Finally got around to compression test - all came in between 142 and 148.

I listened again for any sign of a valve tick but couldn’t hear anything. Both valve covers sound basically the same when it’s idling.

Then I pulled the front injectors and saw this:

It is mostly a gassy goop, but there is definitely some grit in there.

Is it normal for injectors to be this dirty? I

Could I have gotten some bad gas? Could this indicate that my fuel filter has failed? Should I clean these or replace them?

Or is this not a red flag at all?

 

A listened to the video and also didn’t hear any ticking that would come from bad rockers.

Those injectors look good, at least the business end of them, which is the tip. The rest of the injector can be filthy and it will not affect its operation.

You probably need to do a leak down test. Compression test alone is not enough in this situation IMO.

 

Test power at the coil connector. I think your issue is electrical.

 

Thanks guys. I was certainly surprised by the gunk on the injectors and naively thought Id found a smoking gun. Then I looked at them through the microscope and found them to be quite clean.

Thanks for the hunch on the coil connection - If I understand correctly, i can unplug all the coils, hook them up one-at-a-time to an incandescent test light, turn the starter, and look for pulsing? Is it a similar test for the fuel injector wiring?

If that all checks out, I’ll move on to the leak down test.

Whether this is related to fuel, electrical, or valves, I am motivated to fix it. This forum is incredible - thank you!

 

That will work, but sometimes it blows the bulb and gives you a false negative. You can pull the coil, put a known good plug on it and ground it, then crank up and look for the spark.

 

I went a bit further in my investigation last night. First I confirmed that all six coils are sparking on their respective plugs.

I don’t have a leak down tester yet, but I did get a new compression tester (my old one was a cheapie from the 1980s). Results were somewhat different.

6 - 150psi
5 - 150psi
4 - 138psi
3 - 150psi
2 - 75 psi
1 - 155psi

The reading on #2 is throwing me for a loop because the code was P0306. I repeated it several times with the same result. I dripped some drops of oil into #2 and it increased a bit to 85psi.

My choice as this point was to button it all back up and hope the misfire would magically go away, or keep digging further to find out what is happening.

With so much already disassembled, I figured i’d take a look under the right (front) valve cover. What a pain in the butt to pull (I’m used to working on my 1972 Dart Swinger with a 318). Finally got it off and nothing looks amiss - cam lobes are all smooth.

So at this point I really have not gained any insight into the problem.

Since I’m this far in, I think it makes sense to check out the rockers. So I ordered the cam holder tools from Amazon.

Anything else I’m missing?

 

A #2 problem with a #6 code makes a tiny bit of sense... They are exact opposite in the firing order, so both pistons move up and down together.

It seems like you have a serious internal issue unless you find a shot rocker that somehow hasn't scarred the cam (highly unlikely). Hopefully it's just a burnt valve.

 

So we're all on the same page, #2 is at the top of your photo, #6 at the bottom.

#2 has an issue for sure. For the rockers to be an issue I'd think TWO rockers/lifters would have to not be opening the valve. more likely a valve to not be closed/burnt as suggested. For any disassembly Id recommend having a few new rockers on hand so you can compare actually tell a suspect one with axial play in the roller from a good one.

a cheap amazon leak-down tester would tell you at least allow you to put air in the cylinder and verify its going out the exhaust, intake, or oilcap. I personaly think thats academic.

I think you would be hard pressed to not be pulling the head, but you'd need the cam holder tools, rockers etc anyways so you might was well start with the valve train inspection.

 

Thanks. This story has certainly gotten sadder. I’m not sure i want to spend 750 to 1000 on another cylinder head and go thru everything i’d need to install it, and have it all actually work out. I’m just a guy with some tools.

I’m going to Oreilly to borrow a leakdown tester to hopefully confirm that one of the valves in that cylinder is screwed.

 

Machine shop rebuilt my heads for $275 each a couple years ago. That'd be the route I go instead of a reman/new one.

 

I’m starting to think I have two separate problems here. The low comp on #2 is certainly concerning, but closer inspection of the #6 lobes of the intake cam seems to be showing early stage rocker failure. I noticed this one looked a little different than all the other lobes.

Then i put the microscope on it and there’s definitely a bit of scoring.

I might very well need to have the head rebuilt, but for now I’m going to change all the rockers on this side, button it all back up, and see how it runs.

 

I’m anxiously awaiting the results of this. I have a strange stumble at 1200 rpm and some shaking. I know something is up but no codes yet.

 

It took a while to get to it, but I finally got this fixed. As mentioned, I started with a CEL/P0306, rough running in gear at idle. No serious tick sound.

I pulled the left (front) valve cover, and used the plastic Amazon cam wedge/chain tension reliever tools to remove each cam one at a time so I could swap the rockers. One of the #6 intake lobes of the cam had a tiny bit of scoring (see pic above) and that rocker had about 1/32” of play in its bearing (all other rockers were still fine). Nonetheless, I swapped all 12 rockers with new Melling 1332 units. Then I carefully got each cam back into position and buttoned it all back up.

It looks like success - CEL is off and it’s running very smoothly. I’ve only gone about 15 miles so far because I still have a brake issue to resolve, but I’m very optimistic it is fixed.

I’m grateful that this triggered a code before any serious damage was done. All it cost me was $130 worth of rockets, $20 for the special tool, and a few evenings of my time. Compare that to the $1200 that a shop wanted just to try and fix the code by changing the plugs and coils.

I seriously can’t believe I had the cams off of a DOHC variable valve timing V6 and the motor lived to tell about it!

 

See? Easy stuff. When I swapped mine, I never removed the cams, just lifted them enough to make room.

 

Sienile -- Thank you so much for your guidance on this and other posts. I hope you know how appreciated you are and how many people you are helping. You've inspired me to upgrade my membership to support this forum.

 

Thanks for this thread. I have no codes, but a vibration at idle. New plugs and engine mounts made no improvement, nor did 3 tanks of E85. I think I need to pull the valve covers.